The zebrafish--Danio rerio--is a useful model for measuring the effects of small-molecule mitigators of late effects of ionizing irradiation.

BACKGROUND/AIM Use of zebrafish models may decrease the cost of screening new irradiation protectors and mitigators. MATERIALS AND METHODS Zebrafish (Danio rerio) models were tested for screening water-soluble radiation protectors and mitigators. Irradiation of embryos and monitoring survival, and measuring fibrosis of the caudal musculature of adults allowed for testing of acute and late effects, respectively. RESULTS Incubation of zebrafish embryos either before or after irradiation in ethyl pyruvate (1 mM) increased survival. Irradiation of adults to 15 to 75 Gy, delivered in single-fraction at 13 Gy/min, showed dose-dependent fibrosis at 30 days, quantitated as physiological decrease in swimming tail movement, and histopathological detection of collagen deposition in the dorsal musculature. Continuous administration of small-molecule radioprotector drugs in the water after irradiation reduced both acute and chronic injuries. CONCLUSION The zebrafish is cost-effective for screening new radiation countermeasures.